#!/usr/bin/env node

const HELP = `
USAGE
  zed-local  [options]  [zed args]

SUMMARY
  Runs 1-6 instances of Zed using a locally-running collaboration server.
  Each instance of Zed will be signed in as a different user specified in
  either \`.admins.json\` or \`.admins.default.json\`.

OPTIONS
  --help           Print this help message
  --release        Build Zed in release mode
  -2, -3, -4, ...  Spawn multiple Zed instances, with their windows tiled.
  --top            Arrange the Zed windows so they take up the top half of the screen.
`.trim();

const { spawn, execFileSync } = require("child_process");
const assert = require("assert");

const defaultUsers = require("../crates/collab/.admins.default.json");
let users = defaultUsers;
try {
  const customUsers = require("../crates/collab/.admins.json");
  assert(customUsers.length > 0);
  assert(customUsers.every((user) => typeof user === "string"));
  users = customUsers.concat(
    defaultUsers.filter((user) => !customUsers.includes(user)),
  );
} catch (_) {}

const RESOLUTION_REGEX = /(\d+) x (\d+)/;
const DIGIT_FLAG_REGEX = /^--?(\d+)$/;

let instanceCount = 1;
let isReleaseMode = false;
let isTop = false;

const args = process.argv.slice(2);
while (args.length > 0) {
  const arg = args[0];

  const digitMatch = arg.match(DIGIT_FLAG_REGEX);
  if (digitMatch) {
    instanceCount = parseInt(digitMatch[1]);
  } else if (arg === "--release") {
    isReleaseMode = true;
  } else if (arg === "--top") {
    isTop = true;
  } else if (arg === "--help") {
    console.log(HELP);
    process.exit(0);
  } else {
    break;
  }

  args.shift();
}

// Parse the resolution of the main screen
const displayInfo = JSON.parse(
  execFileSync("system_profiler", ["SPDisplaysDataType", "-json"], {
    encoding: "utf8",
  }),
);
const mainDisplayResolution =
  displayInfo?.SPDisplaysDataType[0]?.spdisplays_ndrvs
    ?.find((entry) => entry.spdisplays_main === "spdisplays_yes")
    ?._spdisplays_resolution?.match(RESOLUTION_REGEX);
if (!mainDisplayResolution) {
  throw new Error("Could not parse screen resolution");
}
const titleBarHeight = 24;
const screenWidth = parseInt(mainDisplayResolution[1]);
let screenHeight = parseInt(mainDisplayResolution[2]) - titleBarHeight;

if (isTop) {
  screenHeight = Math.floor(screenHeight / 2);
}

// Determine the window size for each instance
let rows;
let columns;
switch (instanceCount) {
  case 1:
    [rows, columns] = [1, 1];
    break;
  case 2:
    [rows, columns] = [1, 2];
    break;
  case 3:
  case 4:
    [rows, columns] = [2, 2];
    break;
  case 5:
  case 6:
    [rows, columns] = [2, 3];
    break;
}

const instanceWidth = Math.floor(screenWidth / columns);
const instanceHeight = Math.floor(screenHeight / rows);

// If a user is specified, make sure it's first in the list
const user = process.env.ZED_IMPERSONATE;
if (user) {
  users = [user].concat(users.filter((u) => u !== user));
}

let buildArgs = ["build"];
let zedBinary = "target/debug/Zed";
if (isReleaseMode) {
  buildArgs.push("--release");
  zedBinary = "target/release/Zed";
}

try {
  execFileSync("cargo", buildArgs, { stdio: "inherit" });
} catch (e) {
  process.exit(0);
}

setTimeout(() => {
  for (let i = 0; i < instanceCount; i++) {
    const row = Math.floor(i / columns);
    const column = i % columns;
    const position = [
      column * instanceWidth,
      row * instanceHeight + titleBarHeight,
    ].join(",");
    const size = [instanceWidth, instanceHeight].join(",");

    spawn(zedBinary, i == 0 ? args : [], {
      stdio: "inherit",
      env: {
        ZED_IMPERSONATE: users[i],
        ZED_WINDOW_POSITION: position,
        ZED_STATELESS: "1",
        ZED_ALWAYS_ACTIVE: "1",
        ZED_SERVER_URL: "http://localhost:3000",
        ZED_RPC_URL: "http://localhost:8080/rpc",
        ZED_ADMIN_API_TOKEN: "secret",
        ZED_WINDOW_SIZE: size,
        PATH: process.env.PATH,
        RUST_LOG: process.env.RUST_LOG || "info",
      },
    });
  }
}, 0.1);
